John, give it a good prime, crack the throttle and just keep flipping it. When I put a new cylinder and piston on my 30 (massive SPS) It took me forever to get it running again.
At first I thought the ignition was bad, checked that nope, then I looked at the spark plug, nope not that. Checked reeds & carb, nope. I finally decided to keep flipping it. Finally it decided to start.